This study proposes to analyze directly the motor disorders and their central neural substrates induced by acute and chronic administration of ethanol. The freely moving rat will be studied by computer analysis of film and video tape recordings of the initiation and maintenance of regulation of locomotor behavior on a treadmill. Electromyographic recordings will determine abnormal actions of specific muscles. Single neuron recordings will be made in sensorimotor cerebral cortex and in cerebellum to obtain information on the precise correlations between changes in neuronal activity and specific motor disorders. This study will provide an understanding of the underlying sensory versus motor dysfunctions induced by ethanol. Work in progress has led to discovery of specific components of the response of sensory cortical neurons which are uniquely altered by intoxicating doses of ethanol. A selective deficit has also been revealed in which the sensory cortex is impaired by ethanol in its ability to phasically gate or reguate locomotor stepping. The proposed research will test the specific hypothesis that errors in movements arise through an ethanol induced defect in attentional neural systems which regulate processing of sensory input induced by movement. The importance of these investigations derives in part from the major social problem resulting from injury and death due to driving of vehicles while intoxicated. Very little is known about how alcohol impairs the brain's ability to produce accurate movements or the series of judgements leading to movements. The aim of this project is to develop an experimental system for describing the precise movement deficits associated with intoxication and for searching for causes at the level of the activity of single neurons in the brain. The idea to be tested is that abnormal movements arise when the brain fails to correctly link sensory (sight sound or touch) and motor areas of the brain to compute the amplitudes and timing of movement.